Quartz Mountain: SUMMARY
The Quartz Mountain property, located in southern Oregon, represents a large low-grade gold resource hosted in Miocene aged rhyolitic and basaltic volcanic rocks. The property was initially explored for mercury in the 1940s and then later became the focus of attention by several junior and major gold exploration companies that conducted exploration programs in the late 1980s and early 1990s.
The Quartz Mountain project is a volcanic-hosted, hot-spring gold deposit located in the Basin and Range Province of south-central Oregon. Gold mineralization occurs extensively within Late Miocene, endogenous, rhyolite porphyry domes and within the adjacent basaltic flows, tuffs and volcaniclastic country rocks. Disseminated, micron-size, native gold mineralization at Quartz Mountain accompanies pervasive silica flooding and quartz veining and is associated with pyrite, maracasite, and stibnite or their oxidized equivalents. Mineralized zones measure up to 300 feet in thickness and 3000 feet in diameter on Crone Hill and up to 100 feet in thickness and 1000 feet in diameter on Quartz Butte. Gold mineralization at Quartz Mountain occurs with silicification and quartz veining in (i) hot spring sinters and vent breccias; (ii) stockworks and hydrothermal breccias within volcanic vents and along intrusive and stratigraphic contacts; and (iii) stratabound zones of replacement mineralization occupying select lapilli tuff and basaltic agglomerate horizons. Structural ground preparation along with primary porosity and permeability are the ore controls evident in all three cases.
Approximately 709 holes totaling 79,876 meters have been drilled into three known resource areas, Crone Hill, Quartz Butte, and Angel Camp. A number of resource estimates were prepared by various companies and consulting firms in the late 1980s. In April 1988, Minproc (U.S.A.) Inc. completed a preliminary feasibility analysis of the Crone Hill and Quartz Butte deposits. This study suggested that these deposits would be economically unattractive in light of their low grade, low gold recovery and total oxide reserves. With some uncertainty surrounding the metallurgical and assay work which formed the basis of the Minproc study, Davy McKee Corporation was retained in May 1988 to re-evaluate the metallurgical process and assay data and, if warranted, produce a full feasibility analysis of the Crone Hill and Quartz Butte deposits. This study was completed in August of 1989 with generally positive conclusions. However, with declining gold prices the property became less attractive to the various owners.
Following the completion of its acquisition of Quartz Mountain, Seabridge commissioned Winters, Dorsey & Company LLC (“WD&C”), a mine engineering consulting company based in Tucson, Arizona to construct a new resource model for the project. At a 0.34 gram per tonne cut-off grade, the WD&C model for Quartz Mountain estimates measured resources of 3.5 million tonnes grading 0.98 grams of gold per tonne (110,000 ounces) plus an indicated resource of 54.3 million tonnes grading 0.91 grams of gold per tonne (1,591,000 ounces) for a total measured and indicated gold resource of 1,701,000 ounces. In the inferred category, the project contains an additional 44.8 million tonnes grading 0.72 grams of gold per tonne (1,043,000 ounces). Seabridge has not determined whether the stated gold resources at Quartz Mountain are not economic at current gold prices of around US$400 per ounce and therefore none of the mineralised material can be classified as a mineral reserve at this time.
